Our furnace is finicky. We thought it was a random intermittent problem but now we think it just doesn't like to run when it gets below around 35 degrees. We usually use a little ceramic space heater while we are plugged in with the heat strip as backup but are headed north and know we are going to be in some evil cold temps so we figure we'll need the furnace. We turned it on the other night and it fired right up, burned for a few minutes, then turned off. When it tried to turn back on it didn't ignite. We hear the fan, then the igniter, then the igniter, then it all turns off and we have to cycle the thermostat controls to turn it back on and it does the same thing. We tested it during the day and it worked fine (sometimes took two shots with the igniter but it did light). Then we tested after it got cold that night and it flaked out again. It usually runs once even when very cold but won't ignite a second time. We checked our propane and it is at 2/3 (on the tank meter, we didn't rely on the idiot lights). So we've had two thoughts, neither of which fit the scenario well: 1) something overheats so after the initial burn, it won't go again... but it tries to go; 2) the propane is freezing/liquifying in the lines so it isn't getting enough to burn... but it lights that first time.

We plan to call the factory but figured we'd hit the owner pros first to see if you can shed light on the problem. As always, your help if VERY greatly appreciated.

Does the stove and fridge work ok? I know you also have a propane connection in the passenger outside compartment. It work ok too?

Determining whether the problem is related to a specific piece of equipment rather than all propane related equipment is important.

If just the furnace, it could be a number of things like air or moisture in the line, or something gumming up the orifice, or not sensing the flame or the ignition board is defective or a bad ground or possibly the flame rod is dirty, etc.

If it is affecting all equipment, it may be more related to the propane. Keeping the tank warm can help in some situations.....(the following borrowed from another site)

LP Gas Pressure

A furnace is a consumer's friend when the outside temperature gets colder. Unfortunately though, cold is an enemy of LP gas. The BTU capacity of LP per volume decreases as the outside temperature gets colder. Therefore, based on how full the LP tanks are, the ambient temperature outside and how many BTU's the furnace is, there may not be enough gas to sustain ignition on the furnace. Using the charts below, let's say that a 40,000 BTU furnace won't fire up, and we also know that the 65 lb. LP bottle on the RV is 40% full and it is 0 degrees F. outside. One's first thought might be that the burner or valve is bad. However, if we use the chart, the vaporization capacity of the tank in these conditions is only 38,500 BTU's. The furnace is not going to perform very well because there is insufficient BTU capacity in the tank. If you were to put an insulated fire resistant blanket over the tanks and a 75 watt light bulb under that, you would probably raise the temperature of the bottles 10-20 degrees and almost double the BTU capacity of the tank. This in turn would allow the furnace to operate properly. So keep in mind that a furnace problem is not always a component problem.

Luckily, I don't think that the time or cost of having a tech look at it will be very much at all. They are fairly simple pieces of equipment.

I was advised to take a look at Trailer Life's RV Repair and Maintenance Manual by Bob Livingston (4th edition). I did and eventually bought a copy, even though it has been out of print for years (got it on eBay). Lots of great info for problems like this, but trying to describe the entire troubleshooting process is a bit difficult here.

Mike, stove works fine this morning and it's below freezing, fridge was on propane for about 6 hours the other day and it worked fine with no faults but it wasn't under 40 degrees. We haven't used the extra propane port yet. I know with propane it isn't necessarily the tank that freezes, it's the lines. Our Boy Scout troop had 11 lb tanks and woke one morning to frozen lines. We learned to turn propane off at the tank and let the stoves and lanterns go until they burned out then turn those off. That cleared the lines enough that the propane worked in the morning. Not as easy to do on the rig but might be needed in bitter cold weather.

I have the Trailer Life "The RV Handbook" by Dave Solberg 4th Edition and "Woodall's RV Owner's Handbook" by Gary Bunzer 4th Edition. However, I never thought to look there until you told me to. Thanks for the help, I'm off to read.

Holly where did you last fill the tank? If it was down south you may have gotten Propane with butane. Butane is used there in the summer but does not work very well when it is cold.Also check the tube inside the furnace door that leads to the burner. Sometimes spiders and other little critters like to build nest in it. All you need do is to blow it out or use a small brush to clean it. I think only one nut holds it on, so you can remove it to clean it.

Tom, John thinks we filled the tank outside of Asheville, NC back in October or November at a KOA. We peered into that little tube with a flashlight and it looks shiny clean (don't tell, the manual says you aren't even supposed to open the cover unless you are a certified tech). We'll see if we can pull the tube and check for critters farther in when it warms up a bit today.

Update on furnace. We pulled the outside cover again and John watched for the little fault lights on the left wall. He could smell propane when it was trying to ignite so we know some propane is getting there. The fault lights were for "ignition fault lockout". We spoke to Kermit and he said if there was a low pressure situation with the propane, it's the refrigerator that gets finicky first and ours works fine as do the water heater and stove. We figure it is something inside the furnace that prevents the ignition during cold temps OR a something restricting the flow to the point it doesn't work when it gets cold. Kermit made it clear he will reimburse for the repairs if it is something Phoenix did. We are in Staunton, Virginia and topped off the tank with 4.7 gallons of "northern" propane just in case. The furnace ran fine - turning on and off and igniting without a problem for an hour or so then refused to ignite at all as soon as it hit around 45 degrees out. It wouldn't light this morning either. (Darn nippy in here even with the heat strip and space heater- got her inside temp up to 48 so far).

Now we just have to land in one place long enough to get the furnace looked at. We called around down in Georgia and one repair shop said they'd need to keep it 3 or 4 days for testing - not a good option when we live in it and don't have any relatives nearby to go Gypsy on. Camping World there had a two week wait for an appointment. Couldn't do that either since we had to run for Maryland. So, once we get to run south again, we'll try to find a certified Atwood repair shop. We prefer to be in a warmer climate so we don't have to winterize and drag all food and freezable products out of the coach.

Just a heads up to anyone thinking of going full time - any time you have to leave the coach where it can potentially freeze you have several steps to take. We stow the dry goods in bins, pack the refrigerator and freezer contents into a collapsible cooler and insulated bag that we carry, go through every cupboard and bin and pull out everything that can freeze and burst or be damaged by cold, then winterize the rig (easy part). We can do all that and pack our travel bag and the cat in about two hours. All but the dry goods go in the car with us and into whatever heated space we are staying in. Then we find a hotel or cabin that allows pets (critters narrow down the options considerably). Our preferred solution is to find someone that lets us camp in their parking lot with electric hook up if possible or get the rig back each night and book a site nearby.

Will post again when we have resolution in case someone else hits this problem. Even if you usually camp only in warm weather, I suggest you test your furnaces when it is below freezing in case yours has the same problem. It would not be fun finding out it doesn't work that one time you get caught in a freeze.

This ignition problem sounds similar to a problem we had with our fridg. Started run, then shut down. I discovered the ignition gap between the igniter and the electrode was too close. I used a flat screw driver to reset the gap. I measured the thickness of the screw driver and marked the thickness needed for the gap. Set the gap. No problem since.

Barry & Sue had posted a website: bryantrv.com listing service manuals. I found the fridg manual which showed me how to solve my problem. I've checked the website for the Atwood manual but no luck. However, there is good info on solving ignition problems and causes. Go down to; Jump down; click on furnace manuals, then Direct spark ignition. I'm going to look at my heater to find the electrode in case I ever have this problem.

I had read some tips on how to get an atwood furnace to light in cold weather and one of the tips was when this happens start up your two burner gas stove first and let it run for a few minutes and then start your furnace. Don't know if this will work but it seems to be something easy to try.

Another tip was that it may be that the flame sensor is not detecting the flame. That is usually the sensor itself or a bad connection in the wiring to it. Clean those connections to be sure - a pencil eraser is a good tool for cleaning contacts. The furnace should run for about 15 seconds if it is the safety shutoff that is stopping it.

I agree with George, Sue, Tom..... In my experience, all of these types of equipment (incl water heaters, home furnaces, etc) operate basically the same. And most failures I've seen have been due to incorrect gap or bad sensor (sometimes a bad control board). I'm a bit stymied by the fact that it works in relatively warmer environments and fails in colder. However, since the home systems are very similar I wouldn't necessarily wait for an RV tech to look at it. I might opt to call a reputable HVAC tech in the area. Might be quicker, and cheaper.

Tom called and recommended we first call Atwood then do a drop in at Camping World in Winchester VA and ask if they can take a quick look. Atwood said it sounded like our propane regulator needed adjustment (Special tool needed to test pressure). We walked in to camping world with massive wind gusts and freezing temps and looked pitiful and cold. The girl at the counter said no quick look, you need an appointment but the service manager walked in just then and took pity on us. He said yes we need an appt. And he could take us right away. The diagnostics showed the ignitor was giving one spark. If we were lucky enough to ignite with one spark, we got heat. We assume it is easier to ignite when it is warm so cold killed our chances. There is a device on the circuit board that controls the igniter and it is faulty. They think we heard a switch click for each ignition attempt instead of a series of clicks made by a normal igniter. They are ordering the part and hopefully it will be here in a week, otherwise we will be stuck in Maryland again.

Holly call Kermit and tell him what you have done and what Camping World found. Ask him if he can help with getting the part. In any case he will want to know because it should still be under warranty. He may be able to over night the part to you or Camping World. Unless you want to pay for it.

Also you might want to check with S&S to see if they can fix it any quicker. They are an Atwood dealer. If none of this works, try calling Atwood again with an up date. Tell them it is darn cold in WV and you live full time in the motorhome. Use your pitty voice again.

Update on the furnace. Camping World in Winchester VA didn't actually order the part until yesterday even though they wrote up the ticket for it on the 13th (something about the bookkeeper being on vacation - lots of parts didn't get ordered). Now they say it is only coming from two hours away so it should be here tomorrow. (So why did we have to wait in the cold for two weeks? We could have driven up to get it in one afternoon). Our conversations with them were not very satisfactory. One excuse they gave was delays caused by the procedure needed to process a warranty claim. We called Atwood again to find out if we could go somewhere else or if we are locked in with them. Funny thing - they never contacted Atwood. They didn't order the part from them - which would have been free. They aren't actually an authorized Atwood service center (some Camping World's are, this one isn't - the service manager told us he was sure they were - he was wrong - you'd think he'd know). I have an email in to Kermit to ask if they contacted him. We doubt it but want to make sure before we walk away from them. We will head south to somewhere warm where we don't need a furnace. There we will find an Atwood Service Center and get it fixed. We DID check the furnace to make sure no parts are missing because Atwood won't send free warranty replacements unless they get the bad part back.

Another oddity. They told us the bad part was a piece on the circuit board that triggers the igniter but the part on the work order that they ordered (yesterday) was the igniter...